The Effect of ZnO Nanoparticles on the Growth of Bacillus subtilis and Escherichia coli O157:H7

Recently antimicrobial nanoparticles such as ZnO have attracted the attentions of scientists. Regarding the antimicrobial effect and low cost of ZnO nanoparticles، these might be emplyed in food industry to reduce the growth of food microorganisms. The object of this study is to evaluate the antibacterial effect of ZnO nanoparticles on Bacillus Subtilis and E. Coli O157: H7، two important spoiling and pathogenic bacteria of food. ZnO nanoparticles have been synthesized by molten salt method and have been characterized by X-ray diffraction، and scanning electron microscopy. Bacillus Subtilis and E. Coli O157: H7 have been inoculated in 2% and 4% w/w ZnO containing tryptic soy broth followed by the plot of their growth curve. Treatments with both 2% and 4% concentrations of ZnO nanoparticles significantly reduced the number of E. Coli O157: H7 (p=0. 001 and p Regarding the results of the present study، ZnO nanoparticles can significantly reduce the number of both bacteria however it seems that the effect for gram negative bacteria might be more dramatic.